The present invention relates to a horizontal output circuit for a cathode ray tube, and more particularly to a horizontal output circuit for correcting pin cushion distortion of a raster.
An example of a conventional horizontal output circuit for correcting pin cushion distortion is described in U.S. Pat. No. 3,906,305. The circuit of the prior art comprises a horizontal resonant circuit and a second resonant circuit connected thereto in series comprising a resonant capacitor, a damper diode, a coil and a charging capacitor. These two resonant circuits are driven by a single horizontal deflection transistor. A parabolic voltage for vertical synchronization is applied across a coil and a capacitor of the second resonant circuit and a current of the second resonant circuit is modulated parabolically. Therefore, a current flowing through the horizontal deflection coil of the first resonant circuit is amplitude-modulated parabolically in the reverse polarity, thereby correcting the right and left pin cushion distortion. According to such a conventional circuit, it is necessary that a voltage in accordance with the degree of correction of the right and the left pin cushion distortion is accummulated in by the charging capacitor of the second resonant circuit. Therefore, the circuit of the prior art has a disadvantage in that the value of the coil inductance of the second resonant circuit must be large.